'When an asteroid hit Earth 66 million years ago, only those feathered maniraptorans that had downsized to about 1 kilogram or so­the birds­were able to survive, probably because their small size allowed them to adapt more easily to changing conditions, the team concludes online today in PLOS Biology.' 'This size reduction was essential for the evolution of flight, says Luis Chiappe, a paleontologist at the Natural History Museum of Los Angeles County in California, who was not involved in the study. "Flight is easier for smaller animals" because it is "a lot less energetically demanding," he says. And during all those millions of years when maniraptorans were changing body size more quickly than other dinos, Chiappe says, "they were experimenting with various degrees of birdness." ' There's only one problem with this "smaller is better to fly" theory: the Pteranodon. While not technically a dinosaur, it lived in the same period, and was presumably closely related to whatever animals birds consider as ancestors. However, I do agree with the "smaller is better to survive asteroids" theory. https://en.wikipedia.org/wiki/Pteranodon 'Pteranodon ... is a genus of pterosaurs which included some of the largest known *flying* reptiles, with wingspans over 6 metres (20 ft).' 'Pteranodon was not a dinosaur. By definition, all dinosaurs belong to eitherorder within Dinosauria, eitherSaurischia or Ornithischia. As such, this excludes pterosaurs. Nonetheless,Pteranodon is frequently featured in dinosaur media and is strongly associated with dinosaurs by the general public.' 'Pteranodon species are extremely well represented in the fossil record, allowing for detailed descriptions of their anatomy and analysis of their life history. Over 1,000 specimens have been identified, though less than half are complete enough to give researchers good information on the anatomy of the animal.' 'An even larger specimen is known ... with a wingspan of 7.25 metres (23.8 ft)' 'While most of a Pteranodon flight would have depended on soaring, like long-winged seabirds, it probably required an occasional active, rapid burst of flapping, and studies of Pteranodon wing loading (the strength of the wings vs. the weight of the body) indicate that they were capable of substantial flapping flight, contrary to some earlier suggestions that they were so big they could only glide' At 11:52 AM 7/17/2016, James Buddenhagen wrote:

no math here ... but to the questions of birds surviving

http://www.sciencemag.org/news/2014/05/how-birds-survived-dinosaur-apocalyps...

On Sun, Jul 17, 2016 at 8:18 AM, Henry Baker <hbaker1@pipeline.com> wrote:

...

"So how did birds survive?"

Excellent question!

Most scientists think that the primary victims were *large* animals, with the possible exception of large animals living in the oceans.

There remained plenty of oxygen in the atmosphere, but also lots of possibly poisonous gasses.

Smaller animals in burrows might have avoided some of the worst fire conditions in the aftermath of an asteroid hit.

We now (post-GPS) know that some birds -- even some very small birds -- can migrate prodigious distances (thousands of miles), in which case birds may have survived on far-flung islands.

I don't know how many burrowing birds there are.